EGFR and esophageal cancer: A study showed that 40–80% of esophageal cancer patients are diagnosed with high expression of EGFR (Hirsch et al., 2017), and erlotinib can be used as an adjuvant therapy for the treatment of esophageal cancer in combination with radiotherapy and chemotherapy (Sutter et al., 2005; Zhong et al., 2020).